Search

Abstract Needs for neutron detection and monitoring in high neutron flux environments are increasing in several different fields. A completely solid-state, current mode bolometric detector is constructed as a solid substrate transition edge sensor based on a high-T $$_c$$ c superconducting meander. The detector consists of four individual pixels of which three pixels include $${^{10}{\hbox {B}}_{4}\hbox {C}}$$ 10 B 4 C neutron absorption layers. The absorbed energy per neutron absorption reaction is modelled and compared to experimental data. The response of the tested detector is directly correlated to a cold neutron beam with a flux of $${1.8\times 10^{8}}\,{\hbox {n}/{\hbox {cm}}^2/\hbox {s}}$$ 1.8 × 10 8 n / cm 2 / s modulated by a slit. The signal is found to be an order of magnitude higher than the thermal background. The dynamics described by the temporal saturation constants is governed by a modulation frequency less than $${1}\hbox { Hz}$$ 1 Hz . The thermal response is dynamic and never fully saturates for $${50}\hbox { s}$$ 50 s exposures. The efficiency for this proof-of-principle design is 1–2%. Possibilities for optimization are identified, that will increase the efficiency to become comparable to existing solid boron-10 detectors. The existing detectors with event-based read-out have limited functionality in high flux environments. The superconducting bolometer described in this work using current-mode readout will pave the way for high flux applications. more...

Abstract Many applications require monitoring of increasingly high neutron flux levels. Pre‐neutron characterization is performed of a superconducting transition edge bolometric device, sensitive to neutrons by an enriched boron carbide (10B4C) layer. Heat from the absorption of neutrons is simulated using an attenuated laser, while the detector is cooled to the critical temperature, Tc. Frequency dependent (4–25 Hz) and constant input power measurements are performed on a 10B4C‐coated and a non‐coated pixel. Results are used to fit a two lumped element thermal model. The effective specific heat is highly dependent on the input pulse duration due to the interconnected stack structure. For modulated pulses, the active volume in the thermal circuit is the full depth of the substrate in the area under the pixel. For constant power input, a large portion of the substrate is heated and the interface conductivities to the cold finger are found to be important. The detectivity is D* = 3.5 × 108 cmHzW−1, and is only slightly lower than similar detectors. Understanding the dynamics of the detector better and using neutron excitation, it is expected that optimizations can lead to an equally good detector for cold to thermal neutrons at flux levels >106 n cm−2s−1. more...